Avoid calling __init__ for classmethod/staticmethod

例に示されている Fire のエントリポイント fire.Fire(SomethingLikeGit) から始め、init、__init__、クラスメソッド、静的メソッドがどのようにディスパッチされるかを追跡してください。既存の .something_like_git ディレクトリがない状態で python something_like_git.py init を再現してください。__init__ を呼び出さずに init を実行でき、通常のインスタンスコマンドでは現在の初期化動作が維持されれば完了です。

Suppose we want a CLI that is similar to git in the sense that we must first call init before interacting with the repo. For this, we aim for the following (simplified/partially implemented) class, which is intentionally similar to GitPythons Repo class (see here):

from pathlib import Path
import fire

class SomethingLikeGit:

  dirname = ".something_like_git"

  @classmethod
  def init(cls, path=None):
    path = Path(path or Path.cwd())
    path = path / cls.dirname
    print("Initializing at", path)
    path.mkdir()
    ...
    print("Done.")

  def __init__(self, path=None):
    path = Path(path or Path.cwd())
    for parent in (path, *path.parents):
      self.path = parent / self.dirname
      if self.path.exists():
        break
    else:
      raise FileNotFoundError(path)

  ...

if __name__ == "__main__":
  fire.Fire(SomethingLikeGit)

When we run the command python something_like_git.py init, it first tries to instantiate the class via __init__, which fails (FileNotFoundError) since it must first create the directory via init.
I think it makes generally more sense if Fire would call classmethods/staticmethods directly on the class without trying to instantiate it. This is usually also how class/static methods are used in a programmatic way (e.g. for git.Repo).

Note that the fix for #113 does not resolve this issue. This is because the path argument for __init__ is (intentionally) optional, so Fire thinks it can call __init__ first. If path wasn't optional, it would behave as wanted: init would be called without first calling __init__.

Anyway, thanks for your great work!